Apologies, I stand correctedIncorrect. On these early Single Rings the serial number is on the inner shaft, not on the comb guard. There is not any markings on the comb guard on this razor. The 1918 Single Rings have the Gillette Diamond and made in USA on the bottom of the comb guards, and a serial number on the top of the comb guard. The G indicator on the early Single Rings inner shaft was indicative of the gold plating. Also the gold scrip case is an indication of an older set.